The smallmouth bass (Micropterus dolomieu) is one of Missouri’s most popular game fish. Biologists from the Missouri Department of Conservation, National Park Service, University of Missouri, and Missouri State University are conducting separate, but complementary, studies on the species in order to better manage its habitat and regulate harvest.

Smallmouths are found predominantly in cool, clear Ozark streams and large reservoirs in the Ozarks, but also sparingly in the upper Mississippi River and its principal prairie tributaries. They thrive in clear streams with silt-free rock or gravel bottoms near riffles away from the main current. Smallmouth bass are generally not found in the northwest or north central portion of the state or in the Bootheel.

With such a far-ranging study subject, citizen participation and a multiagency effort ensures a solid approach to studying this popular fish. Monitoring techniques like telemetry (using equipment to record and transmit data from a distance), and tagging will help biologists monitor fish movements and behavior. Three different types of tags were used in these studies: harvest-data tags (collected and reported by anglers), radio transmitter tags (monitored at intervals by scientists along the waterways), and temperature tags (recording tags collected by scientists). Not all tags were used in each study. Biologists use the information collected to help make management decisions for the species.

Department of Conservation Study

The Department of Conservation tagged smallmouth bass in the Castor, Black, and Current rivers, the North Fork of White River, and Courtois Creek, incorporating various sizes of waterways. Fisheries management biologists for the five streams affixed the external harvest tags to the wild-caught fish. Anglers were asked to report where and when they caught tagged fish and whether they were kept or released. They also provided measurements of the fish.

In a complimentary study, the Department also surveyed angler opinions by mail. This study gathered angler attitudes and opinions and estimated effort spent fishing for smallmouth bass in Missouri streams.

Jennifer Girondo, Department of Conservation fisheries management biologist and chair of the Smallmouth Bass Working Group, is coordinating the studies on smallmouth bass harvest rates and the angler mail survey. Girondo says the group is learning more about the fish’s life history and has gotten an updated depiction of smallmouth anglers. (Visit the Department’s Smallmouth Bass Management page at mdc.mo.gov/node/5857 to view the full Smallmouth Bass and Rock Bass Fishing survey and more.)

“We need to ensure that our smallmouth bass fishing regulations are appropriate for providing quality fishing experiences for all Missouri stream anglers,” Girondo said. “Appropriate regulations entail that we understand where and how smallmouth use our streams and where and how anglers use smallmouth bass.”

University of Missouri Study

The University of Missouri is conducting telemetry studies to learn more about smallmouth behavior.

Temperature tags that are surgically placedinside the fish were used in this study to record the temperature the fish experienced at set time intervals. “These tags tell us if the fish are using warmer or colder water than we expected them to,” says Craig Paukert, leader of the Missouri Cooperative Fish and Wildlife Research Unit at the University of Missouri. “We want to understand how fish growth may change if the climate changes.”

“Working with other agencies enables us to easily share ideas about how to do the study and what the results mean,” says Paukert. “We help each other collect data and share equipment, and we can plan our studies to maximize the knowledge we gain while minimizing duplicate efforts.”

National Park Service Study

Complementing the studies conducted by the Department of Conservation and the University of Missouri is the National Park Service study on how large springs influence aquatic life in adjacent streams.

Hope Dodd, of the National Park Service, and Mike Siepker, a resource scientist with the Department of Conservation, conducted a fish telemetry study using surgically implanted radio transmitter tags at Big Spring along the Current River to document the use of springs by smallmouth bass and the timing of their movement into and out of springs. Their group tagged and tracked 30 fish for a year, documenting the temperature and habitat used by smallmouth bass within the river and the spring.

Dodd says that the telemetry study data will help biologists understand the timing of movement and use of springs and river habitats by smallmouth bass, a fish species whose distribution and abundance in the Ozarks has declined, due in part to increased water temperatures over the years.

In addition to the main study, a Missouri State University graduate student completed a 24-hour radio telemetry study of some of the smallmouth bass tagged in the river. This provided information on how much movement these fish exhibit over a 24-hour period, including the specific habitat that they selected.

“Combining the temperature data with the smallmouth bass telemetry work, we can assess the importance of springs in regulating water temperatures in the river and determine the importance of springs as refuges for fishes that require cooler temperatures,” says Dodd.

Combined Findings

Although these studies are different, their combined results will give biologists a better picture of smallmouth habits and management needs.

Findings from all three studies are interesting. From the temperature data, the group learned that each spring has a relatively constant temperature throughout the year, but not all springs have the same average temperature. From the radio telemetry studies, they found that the timing of movement from Big Spring into the river was influenced by temperature. Smallmouth bass inhabited the warmer water of Big Spring in late winter, and moved into the river once river temperatures warmed to similar temperatures of the spring. By late fall, when river temperatures cooled below that of Big Spring, fish began returning.

This is just a sampling of the data from these studies. For more interesting facts, see the sidebar Smallmouth Bass Study Findings (to the right). For more information about these studies, contact your regional Department of Conservation office. Also, be sure to check out our Smallmouth Bass Fishing page at mdc.mo.gov/node/5853 for great tips and tricks and fishing locations.

Fun Facts

Small Fin: The smallmouth bass was given the scientific name Micropterus dolomieu by the French naturalist Count Bernard Germain Etienne De La Ville Lacepede. Micropterus is Latin for “small fin.” The second name, dolomieu, was after M. Dolomieu, a French mineralogist for whom dolomite, a rock type, is also named.

Nicknames: Smallmouth have a number of local names. They include: brown bass, brownie, bronze back, green trout, jumper, Oswego bass, redeye bass, river bass, and smallie.

The Unbass: The smallmouth bass is actually a member of the sunfish family (one of the largest freshwater sport fish families). Smallmouth are also grouped with the largemouth and spotted (Kentucky) bass, which are collectively known as black bass.

Cool Fish: Smallmouth bass shun waters with temperatures that commonly exceed the mid-80s. Temperatures over 90 degrees can be lethal. Smallmouth bass also need a great amount of dissolved oxygen. A dependable stream flow, streamside shade and a modest current are also important to riverine smallmouth bass.

Spring Spawn Hazards: Research on smallmouth bass has shown no relationship between the number of spawning fish and the success of the spawn. The strength of the year’s hatch depends solely on water conditions — in particular, a sudden cold snap or muddy floodwaters can kill eggs and fry.

Tail Fin I.D.: The tail fin on young smallmouth is distinctly tri-colored with a black vertical bar separating the yellowish fin base from the whitish fringe along the rear margin of the fins.

Follow the Feeder: An interesting habit of smallmouth bass is to follow a large turtle or sucker as they dig or root along the bottom, pouncing on any insects or crayfish disturbed by the feeding activity.

18-Year-Old Fish: Smallmouth bass have a maximum life expectancy of about 18 years; however, only a few ever live even half that long.

Old Fish: It can take 8–10 years for a smallmouth to reach 18 inches long in Ozark streams.

For the Record: The current Missouri state record is 7 pounds, 2 ounces, caught in 1994 from Stockton Lake.

Find MO Fish App

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Buy Permits Online!

See our list of available fishing permits and buy yours online at mdc. mo.gov/fishing. Fishing permits, unless noted otherwise on the permit itself, are valid from the date of purchase through the last day of February. Permits may be printed and used immediately.

Smallmouth Bass Study Findings

The majority of smallmouth bass were harvested early in the season.

Wade/bank fishing is the most popular method, followed by float fishing, and then powerboat fishing.

82 percent of anglers who responded fish for smallmouth bass.

High water and warming water temperatures triggered smallmouth bass movement in the Current River.

The fish preferred deeper waters of 5 feet or more.

Open water, logs, and boulders are used at different times of the day and year.

The species left Big Spring when river and spring temperatures were similar.

Also called "brown bass," "brownie" and "bronzeback," this popular gamefish is found predominantly in cool, clear Ozark streams and large reservoirs in the Ozarks. Found sparingly in the upper Mississippi River and its principal prairie tributaries that have clear water and permanent flow.

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